4. RASTER POSITION SWITCHING CIRCUIT
4-1. Outline
So, adjust the center of the picture to the center of the screen
When the vertical screen position adjustment is carried out | in advance under the output V sync delayed. | |
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on the projection TV, DC current is directly flown in the | To do this, lower the raster position by flowing a DC current | |
vertical deflection yoke and the raster cannot be moved up | ||
to the deflection yoke in the CINEMA and SUBTITLE | ||
and down. (Because the raster is moved, the color distortion | ||
mode. | ||
may occur.) Accordingly, the vertical screen position | ||
The operation above is carried out by the vertical screen | ||
adjustment is carried out by the following method. (Only in | ||
position SW circuit. | ||
CINEMA and SUBTITLE mode) | ||
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V sync pulse output from Q501 sync. separation circuit is |
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once input to WAC, delayed and then output. The deflection | ||
circuit operates with the delayed sync signal. The screen | When CINEMA and SUBTITLE are selected in the screen | |
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upper side position moves up and down by varying the delay | mode, a zoom signal is input to the base of Q362 from the | |
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time. When the vertical position adjustment is carried out | autolive circuit and Q362 turns on. Then, Q363 turns off | |
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by WAC, the followings must be considered. | and the base of Q364 develops H and Q364 turns on. The | |
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WAC becomes “through” except for CINEMA and | inverted DC current flows into the vertical deflection yoke | |
SUBTITLE mode. | from +35V power supply line. |
The phase of the output V sync must not advance from that of WAC input V sync. If it advances, Vertical jitter may occur when performing the search operation and the vertical position adjustment of a VTR.
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| R363 | R364 |
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| R362 | 2R | KETSU | R365 |
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Fig. | R360 | 220 |
| R366 |
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33K | 1R5.6K |
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| 1R5.6K | 33K |
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| Q364 |
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| Q362 | R361 2SC2023 |
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| R367 | Q366 | |
| 12K |
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| 12K | ||
| RN1204 |
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| RN1204 | ||
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| Q363 |
| Q367 |
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| 2SC2023 | Q365 |
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| 2SC1815Y |
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| 2SC1815Y |
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| D361 |
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| S5965G |
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| +35V |
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| +12V |
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| P360 |
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Fig. |
Screen |
mask |
position |
Nomal mode (4:3, Full, Dramatic Wide)
| Screen | |
Raster position | mask | |
position | ||
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Mode in which the opposite current flows into D Y (Cinema)
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